Jane Espenson makes the case for finding the essence before writing the jokes:
I guarantee you that they did not start working on the latest episode by thinking of funny things that could happen in a pottery class. They started by thinking about their characters, what they believe, and where they’re weakest.
Find your characters’ vulnerable spots and poke them and you’ll find a story. The idea that Jeff was over-praised as a child, resulting in a self-image that needs correction is not hilarious. It’s grounded and real — which allows for more license when writing the jokes.